A study on the influence of prosthetic interface material in transtibial amputees' gait

Interfaces of transtibial prosthesis have an important role in the transmission of ground reaction forces, damping gait loads and tissue protection.

This work aims to study the influence of prosthesis interfaces on amputees' gait and perception on pain, comfort and the overall interface/prosthesis system.

Commercial samples of three different interface materials were selected: block copolymer (Material I), silicone gel (Material II) and silicone elastomer (Material III). Using standardized prosthesis, four amputee subjects performed gait tests at three imposed cadences in a barometric platform. The subjects also filled in a questionnaire about their perception.

Material II presented the highest asymmetries of vertical ground reaction forces and was perceived as the most painful and uncomfortable. Material III led to the most symmetric load distribution between legs and was perceived as the most comfortable. Material I showed better overall biomechanical behavior and better subject's perception.

Material III showed appropriate characteristics for lower levels of activity for which it is recommended. Prescription of Material II should be rethought, as it is only adequate for specific and occasional situations. Material I should be considered adequate for both active and less active amputees. When correlating the subjects' perception with the interface properties, we concluded that the mechanical properties are the most influential.